Get a multimeter and learn how to use it!
Even if you do have the money to call an electrician for every anomaly that you experience on your boat, you must still acquire at least some basic electrical knowledge if you’re planning on heading out cruising. While we’re not in the aforementioned category of cash-rich cruisers, we do have a couple of friends who are electricians. Even so, if we do send them an email asking them for advice, they are still likely going to want us to check connections and report back voltages measured at various points. In order to do this, you’ll need to have at least a basic electrical multimeter on board, and a bit of knowledge on how to use it. Just like all of the various sailing words that you’ve had to learn, Volts, Amps and Ohms can not be completely foreign terms to you. Get studying!
It may shock you to hear how often I have to use this multimeter